Although many excellent results have been obtained in the individual areas of specialization related to alcohol- and drug-induced liver injury, few multidisciplinary attempts, if any, have been made to combine techniques to unravel the molecular, cellular and physiological mechanisms that underlie the pathogenesis of the liver injury due to alcohol. The multidisciplinary experimental strategy adopted in the present grant proposal originated from the newly developed and unique micro-light guide tissue photometric technique which will enable us to measure dynamic metabolic processes occurring in microregions within the liver lobule. Intralobular measurements are essential to understand the mechanisms of liver injuries caused by alcohol, drugs and carcinogens since injuries are often confined to the pericentral zone. The objectives of this research are divided into four categories: (1) To obtain fundamental information on the intralobular heterogeneity in oxygen tensions, metabolites, local oxygen metabolism, mixed-function oxidation and conjugation reactions, and microcirculation. (2) To evaluate the hypothesis that the mechanism of the pericentral hepatic injury due to ethanol involves alterations in the intralobular oxygen gradient. (3) To identify the biochemical and physiological mechanisms underlying the pericentral necrosis induced by drugs (e.g., acetaminophen). (4) To prevent the toxic effects of ethanol and acetaminophen with chronic and acute administration of drugs, hormones and vitamins and manipulations of nutritional state. Livers from normal and alcohol-treated rats will be perfused. Physiological (micro-light guide and surface PO2 electrode), biochemical (tissue metabolite assay and micro-dissection chemical analysis), and structural methods (light and fluorescence microscopy, scanning and thin-section transmission electron microscopy, and low-temperture NADH fluorescence photography) will be employed. Thus, for the first time, it will be possible to evaluate the hypothesis that the development of local anoxic zones around the central vein is responsible for alcohol-induced liver injury. In addition, these studies may provide molecular mechanisms on which to base rational treatments of fatty liver and cirrhosis due to alcohol and drugs.